1. Field of the Invention
The present invention relates to a workpiece retainer for a bonding apparatus.
2. Prior Art
Japanese Utility Model Application Publication (Kokoku) No. H06-21241 discloses one example of workpiece retainers used in a bonding apparatus. In this workpiece retainer, slits are formed so as to surround a bonding window, so that the retainer presses the numerous leads of a lead frame against a heating block.
The advantage of this workpiece retainer is that it can press the leads against the heating block in a uniform fashion. However, in this prior art retainer, slits are merely formed as a combination of substantially angled C-shaped slits that are arranged so as to face the bonding window. Accordingly, it has problems. Because of such a slit shape, the thermal expansion of the workpiece retaining portions of the workpiece retainer caused by the heating block is not well absorbed, and as a result the workpiece retaining portion which is a part of the workpiece retainer is deformed.
Accordingly, the object of the present invention is to provide a workpiece retaining device or a retainer used in a bonding apparatus that can effectively absorb the thermal expansion of the workpiece retaining portion of the workpiece retainer and that can securely retain the leads of a lead frame over the entire retention range.
The above object is accomplished by a unique structure for a workpiece retainer in which: a plurality of first slits are formed so as to surround bonding windows opened in the retainer; second slits are formed so as to respectively extend to the outside from the end portions of the first slits, thus forming first connecting areas; and third slits are further formed so as to extend perpendicular to the first connecting areas on the outside of the second slits, thus forming second connecting areas.
In this structure, the bonding windows are provided so as to correspond in number to the bonding portions of a lead frame that has a plurality of rows of bonding portions; and in addition, workpiece retaining portions are formed along the bonding windows so that the retaining portions are located on the undersurfaces of both sides of each bonding window.